Tech Universe: Friday 11 April

SPARKING PROGRESS: Some spinal cord injuries prevent people from voluntarily moving their legs. US researchers implanted an epidural stimulator in 4 people paralysed in accidents. The result was that 3 of them were then able to voluntarily move their hips, ankles and toes. This worked because once the signal was triggered, the spinal cord reengaged its neural network to control and direct muscle movements. Over the course of the study the participants were able to activate movements with less stimulation, and their overall health improved. The researchers now hope such stimulation may one day form part of the therapy to treat paralysis. A knee jerk today could become a footfall tomorrow.

THE HEART OF ENCRYPTION: Encrypting data is one way to keep it confidential, but exactly how to do that encryption is always a challenge. Scientists at Lancaster University claim their new method, inspired by human biology, is nearly unbreakable. The heart and lungs need to work together in a specific rhythm which is constantly changing.

The scientists were able to use the way the intervals change to create a scheme that offers an infinite number of choices for the secret encryption key shared between the sender and receiver. That makes it virtually impossible for hackers and eavesdroppers to crack the code. Several different information streams can transmit simultaneously so all devices in a group, for example all the devices in one home, could operate on one encryption key rather than each needing its own. Perhaps that ever-changing heartbeat could also be used for authentication too?

THE HEART OF TIME: You and I are probably happy enough to know that it's roughly 8 am when we meet for coffee, but some applications need to know the exact time down to the tiniest fraction of a second, as with GPS or banks processing financial transactions, for example. One organisation that operates a reference clock to calibrate other timekeepers is the US National Institute of Standards and Technology. Their new NIST-F2 cesium-based atomic clock will neither gain nor lose one second in about 300 million years. That makes it around 3 times as accurate as its predecessor. The clock measures the frequency of a particular transition in the cesium atom used to define the second — a transition that takes place 9,192,631,770 times per second. The previous NIST clock ran at around room temperature, but the new one is cooled to minus 193 C which dramatically lowers the background radiation, reducing measurement errors. That's a steady heartbeat.

SUNNY OUTLOOK: Unfortunately the process of making solar cells may require quite a lot of energy generated from less environmentally-friendly sources. Researchers at Oregon State University though may have a way to use solar power to create the cells too. Using their method copper indium diselenide is continuously processed in a microreactor to produce nanoparticle inks that make solar cells by printing. The researchers used artificial light focused on the solar microreactor to rapidly heat it, but direct sunlight could be used instead. The system synthesised solar energy materials in minutes, a fraction of the time required by existing processes. Reduced manufacturing time should mean lower costs. The solar absorbing layers this system produces are also much thinner than more conventional silicon cells, meaning they could be easier to incorporate into building components such as windows or roof shingles. It's almost a perpetual motion system, using solar energy to create collectors of solar energy.

QUIET RUNNINGS: Ships make quite a lot of noise as they travel through the world's oceans. Some noise comes from propellers which create and release tiny bubbles as they turn in the water, making a loud roar. All the noise stresses whales, may be linked to dolphin strandings and is detrimental to squid, octopuses and cuttlefish. Now the International Maritime Organization has created guidelines to make some ships quieter, recommending measuring and minimising the noise in newly built ships and reducing it in existing ones. The same modifications that reduce noise also help shipping companies save fuel, so that's two reasons to make changes. You'd think that the companies would have always cared about fuel efficiency, even if they weren't concerned about the effect on marine ife.